1. Field of the Invention
This invention relates to a shorts type absorbent article such as a shorts type disposable diaper and a shorts type sanitary napkin having a joined section which is excellent in strength, feel and peelability.
2. Description of the Related Art
Heretofore, a wide variety of shorts type absorbent articles have been proposed, which includes a liquid-permeable topsheet, a liquid-impermeable antileakage sheet and a liquid-retentive absorbent core, and in which opposing left and right side edge portions of a stomach-side portion and opposing left and right side edge portions of a back-side portion are joined together to thereby form a pair of joined sections.
However, in the conventional shorts type absorbent articles, the joined section is formed in such a manner that it is sandwiched and pressed between a joining block having an even surface and another joining block having concavity and convexity configurations. Thus, the joined section comprises first regions which are pressed from the both surfaces and second regions which are pressed from only one surface thereof. In the conventional absorbent articles having such a joined section, since the joined section is stiff, it irritates the wearer""s skin and the feel is not good enough.
There have also been contemplated those in which the joined section comprises first regions which are joined by being pressed from both surfaces and second regions which are not pressed from either surface. Absorbent articles having such a joined section are greatly reduced in stiffness but only at the sacrifice of the joining strength. Moreover, those absorbent articles have such an inconvenience that the regions (first regions), which are pressed from both surfaces, are extremely reduced due to swaying on an actual machining tool and a desired joining strength is unobtainable.
Furthermore, such a shorts type disposable diaper as disclosed in Japanese Utility Model Laid-Open Publication (Kokai) No. Hei 9-287 is known. In this disposable diaper, a nonwoven fabric containing thermoplastic fibers is thermally bonded to opposite side edge portions of the shorts by varying the joining width such that a joined section having difference in joining strength is arranged adjacent to the vertical direction of the shorts.
However, in the absorbent article of this technique, since the joined section, which is varied in joining width so as to have difference in joining strength, is arranged adjacent to the vertical direction of the shorts, the feel is bad. Moreover, since the joining strength is of two stages, peelability is not good. Furthermore, there is a fear that discharged wastes leak through a gap between the adjacent joined sections.
It is, therefore, an object of the present invention to provide a shorts type absorbent article which is provided with a joined section having sufficient strength, excellent feel and texture and superior peelability.
From one aspect of the present invention, the above object has been achieved by providing a shorts type absorbent article comprising a liquid-permeable topsheet, a liquid-impermeable antileakage sheet and a liquid-retentive absorbent core, opposing left and right side edge portions of a stomach-side zone and opposing left and right side edge portions of a back-side zone being joined together to thereby form one pair of joined-sections, wherein the joined sections include securely joined sections which are joined by being pressed substantially from both a surface on the side of the stomach-side zone and a surface on the side of the back-side zone, moderately joined sections which are joined by being pressed substantially from either the surface on the side of the stomach-side zone or the surface on the side of the back-side zone and non-joined sections which are not substantially pressed from either the surface on the side of the stomach-side zone or the surface on the side of the back-side zone, the joined sections having three or more stages of thickness in section.
From another aspect of the present invention, the above object has been achieved by providing a method for manufacturing the above-mentioned absorbent article, comprising a joining step for forming one pair of left and right joined sections by pressing one pair of joining blocks having predetermined concavity and convexity configurations from both the surface on the side of the stomach-side zone and the surface on the side of the back-side zone, the one pair of joining blocks used in the joining step, having the concavity and convexity configuration formed by arranging a plurality of convexities linearly at predetermined intervals, a cross angle xcex1 formed between straight lines formed by the convexities of one of the joining blocks and straight lines formed by said convexities of the other side of the joining block being set to 0 degree less than xcex1 less than 180 degree, or otherwise the one pair of joining blocks, having the concavity and convexity configuration formed by arranging a plurality of convexities linearly at predetermined intervals, a cross angle xcex1 between straight lines formed by the convexities of one of the joining blocks and straight lines formed by the convexities of the other of the joining blocks being set to xcex1=0 or xcex1=180 degree, and a ratio between a width of each convexity of the one joining block and a width of each convexity of the other joining block being set to 1.3 or more.
The absorbent article of the present invention has sufficient strength, excellent feel and peelability in its joined sections.